This invention relates to dental devices, and more particularly to dental handpieces and/or root-canal (endodontic) instruments, including rotary instruments, arranged for microwave/RF radiation, for aiding in cleaning, disinfecting, shaping and/or sealing the inner confines of a tooth.
Root-canal instruments include files, reamers, rasps, broaches, Hedstrom (H-type) files, and the like. To the uninitiated, many of these instruments have the appearance of a conventional fluted drill bit, but in general the endodontic instruments differ in at least two aspects, namely that they are tapered from distal to proximal ends, and in that the distal end or tip is not shaped for removal of material. Since such instruments are designed for removal of material from their sides rather than from their ends, relatively large bending moments are encountered when they are employed, and the taper provides thickness near the proximal end to resist excessive bending. The shape of the tip is chosen to tend to prevent the possibility of unwanted punctures during procedures. Drills are also used in such procedures. An overview of such devices and their modes of use is given in an article entitled INSTRUMENTS FOR ROOT CANAL PREPARATION, by Cohen & Burns, published at pp 391-409 of Pathways of the Pulp, Mosby Year-Book Inc., 1991. As described therein, many of the instruments are operated manually or hand-driven, to enable the user to maintain a tactile sensation or feel of the contact. Hand-operated quarter-turn rotary and full rotary drivers have been used in conjunction with such instruments. Engine-operated instruments are also used, but care must be taken to prevent perforation and to prevent removal of excessive dental material.
Barbed broaches are used in root-canal procedures to remove intact pulp tissue, by rotating the broach in the pulp to entangle the tissue in the barbs, and removing the entire pulp. When the pulp has degenerated, it has insufficient cohesion to allow removal as a mass.